It's the same employer, just the ownership that changed hands.

It is the current managements "fault". They bought the company, all it's assets, all it's liabilities. They don't get to conveniently decide they get the company, but none of it's debts.

> They were promised that someone else would reward them.

They were promised Twitter would reward them, by people with the authority to make binding promises on behalf of Twitter.

> That looks like a problem coming from the first employer.

There is no first/second employer here. They were employed by Twitter before the acquisition, they were still employed by Twitter afterwards.

Of course it is! Elon bought Twitter and all that came with it, including all the contracts set up by the previous management.

You could have an argument that if Twitter intentionally nuked their entire company between signing the deal and the acquisition date, the old management probably committed some kind of fraud, but that's not the case here; these bonuses seem pretty reasonable for a company like Twitter before Elon took over, to ensure the transition goes well.

See the issue?

Here’s another way of framing this point: when selling a company, which liabilities do you feel should follow through to new ownership and which shouldn’t? Tax obligations? Real estate mortgages? Employee compensation?

Selling a company shouldn’t be a one-way risk valve. You punch the ticket, you take the ride.